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  <title>Energia Reference - Boolean </title>
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<p class='vspace'></p><h1>Boolean Operators </h1>
<p>These can be used inside the condition of an <a class='wikilink' href='If.html'>if</a> statement.
</p>
<p class='vspace'></p><h3>&amp;&amp; (logical and)</h3>
<p>True only if both operands are true, e.g.
</p><pre>
if (digitalRead(2) == HIGH  &amp;&amp; digitalRead(3) == HIGH) { // read two switches 
  // ...
} 
</pre><p>is true only if both inputs are high.
</p>
<p class='vspace'></p><h3>|| (logical or)</h3>
<p>True if either operand is true, e.g.
</p><pre>
if (x &gt; 0 || y &gt; 0) {
  // ...
} 
</pre><p>is true if either x or y is greater than 0.
</p>
<p class='vspace'></p><h3>! (not)</h3>
<p>True if the operand is false, e.g.
</p><pre>
if (!x) { 
  // ...
} 
</pre><p>is true if x is false (i.e. if x equals 0).
</p>
<p class='vspace'></p><h4>Warning</h4>
<p>Make sure you don't mistake the boolean AND operator, &amp;&amp; (double ampersand) for the bitwise AND operator &amp; (single ampersand). They are entirely different beasts.
</p>
<p class='vspace'></p><p>Similarly, do not confuse the boolean || (double pipe) operator with the bitwise OR operator | (single pipe).
</p>
<p class='vspace'></p><p>The bitwise not ~ (tilde) looks much different than the boolean not ! (exclamation point or "bang" as the programmers say) but you still have to be sure which one you want where.
</p>
<p class='vspace'></p><h4>Examples</h4>
<pre>
if (a &gt;= 10 &amp;&amp; a &lt;= 20){}   // true if a is between 10 and 20

</pre>
<p class='vspace'></p><h4>See also</h4>
<ul><li><a class='wikilink' href='BitwiseAnd.html'>&amp;</a> (bitwise AND)
</li><li><a class='wikilink' href='BitwiseAnd.html'>|</a> (bitwise OR)
</li><li><a class='wikilink' href='BitwiseXorNot.html'>~</a> (bitwise NOT
</li><li><a class='wikilink' href='If.html'>if</a>
</li></ul><p class='vspace'></p><p><a class='wikilink' href='index.html'>Reference Home</a>
</p>
<p class='vspace'></p><p><em>Corrections, suggestions, and new documentation should be posted to the <a class='urllink' href='http://forum.43oh.com/forum/28-energia/' rel='nofollow'>Forum</a>.</em>
</p>
<p class='vspace'></p><p>The text of the Energia reference is licensed under a
<a class='urllink' href='http://creativecommons.org/licenses/by-sa/3.0/' rel='nofollow'>Creative Commons Attribution-ShareAlike 3.0 License</a>.  Energia reference is based on Arduino reference.  Code samples in the reference are released into the public domain.
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